Flame retardant composition comprising a high melt strength polypropylene

Abstract

The present invention is related to a flame retardant polypropylene composition (C) comprising a propylene polymer (PP), a nitrogen-containing flame retardant (FR) and an antidripping-agent (A) being a high melt strength polypropylene (HMS-PP) having a F30 melt strength determined according to ISO 16790:2005 of at least 20 cN. Further, the present invention is related to the use of a high melt strength polypropylene (HMS-PP) having a F30 melt strength determined according to ISO 16790:2005 of at least 20 cN as an antidripping-agent as well as an article comprising the flame retardant polypropylene composition (C).

1 . A flame retardant polypropylene composition (C), comprising:
 i) 23.0 to 80.0 wt.-% of a propylene polymer (PP),   ii) 10.0 to 40.0 wt.-% of a nitrogen-containing flame retardant (FR), and   iii) 10.0 to 37.0 wt.-% of an antidripping-agent (A) being a high melt strength polypropylene (HMS-PP) having a F 30  melt strength determined according to ISO 16790:2005 of at least 20 cN, and   iv) 0.0 to 15.0 wt.-% of carbon black (CB),   based on the overall weight of the flame retardant polypropylene composition (C),   wherein the flame retardant polypropylene composition (C) does not contain glass fibers.   
     
     
         2 . The flame retardant polypropylene composition (C) according to  claim 1 , wherein the propylene polymer (PP) is a heterophasic propylene copolymer (HECO) comprising:
 a) a matrix (M) being a polymer of propylene, and   b) an elastomer (E) being a copolymer comprising units derived from propylene and ethylene and/or C 4  to C 8  α-olefin.   
     
     
         3 . The flame retardant polypropylene composition (C), comprising:
 i) a propylene polymer (PP) being a heterophasic propylene copolymer (HECO) comprising   a) a matrix (M) being a polymer of propylene, and   b) an elastomer (E) being a copolymer comprising units derived from propylene and ethylene and/or C 4  to C 8  α-olefin,   ii) a nitrogen-containing flame retardant (FR),   iii) an antidripping-agent (A) being a high melt strength polypropylene (HMS-PP) having a F 30  melt strength determined according to ISO 16790:2005 of at least 20 cN, and iv) optionally carbon black (CB).   
     
     
         4 . The flame retardant polypropylene composition (C) according to  claim 3 , comprising:
 i) 20.0 to 65.0 wt.-% of the propylene polymer (PP),   ii) 10.0 to 40.0 wt.-% of the nitrogen-containing flame retardant (FR),   iii) 10.0 to 40.0 wt.-% of the antidripping-agent (A), and   iv) 0.0 to 15.0 wt.-% of carbon black (CB),   based on the overall weight of the flame retardant polypropylene composition (C).   
     
     
         5 . The flame retardant polypropylene composition (C) according to  claim 1 , wherein the flame retardant polypropylene composition (C) is free of halogens. 
     
     
         6 . The flame retardant polypropylene composition (C) according to  claim 1 , wherein the overall amounts of the propylene polymer (PP), the nitrogen-containing flame retardant (FR), the antidripping-agent (A) and optionally the carbon black (CB) together make up at least 90 wt.-% of the flame retardant polypropylene composition (C). 
     
     
         7 . The flame retardant polypropylene composition (C) according to  claim 1 , wherein the nitrogen-containing flame retardant (FR) comprises a first nitrogen-containing phosphate (FR1) and a second nitrogen-containing phosphate (FR2). 
     
     
         8 . The flame retardant polypropylene composition (C) according to  claim 7 , wherein the weight ratio between the first nitrogen-containing phosphate (FR1) and the second nitrogen-containing phosphate (FR2) is in the range of 60:40 to 40:60. 
     
     
         9 . The flame retardant polypropylene composition (C) according to  claim 7 , wherein the first nitrogen-containing phosphate (FR1) is melamine polyphosphate and the second nitrogen-containing phosphate (FR2) is piperazine pyrophosphate. 
     
     
         10 . The flame retardant polypropylene composition (C) according to  claim 2 , wherein the heterophasic propylene copolymer (HECO) has:
 i) a comonomer content in the range of 4.0 to 17.0 mol-%, and/or   ii) a xylene cold soluble fraction (XCS) in the range of 7.0 to 25.0 wt.-%, based on the overall weigh of the heterophasic propylene copolymer (HECO).   
     
     
         11 . The flame retardant polypropylene composition (C) according to  claim 10  wherein the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO) has:
 i) a comonomer content in the range of 25.0 to 65.0 mol-%, and/or 
 ii) an intrinsic viscosity (IV) measured according to ISO 1628/1 (at 135° C. in decalin) below 3.5 dl/g. 
 
     
     
         12 . The flame retardant polypropylene composition (C) according to  claim 1 , wherein the high melt strength polypropylene (HMS-PP) has a melt flow rate MFR 2  (230° C., 2.16 kg) determined according to ISO 1133 in the range of 0.5 to 15.0 g/10 min. 
     
     
         13 . The flame retardant polypropylene composition (C) according to  claim 1 , having a melt flow rate MFR 2  (230° C., 2.16 kg) determined according to ISO 1133 in the range of 1.0 to 30.0 g/10 min. 
     
     
         14 . (canceled) 
     
     
         15 . An article, comprising the flame retardant polypropylene composition (C) according to  claim 1 . 
     
     
         16 . The flame retardant polypropylene composition (C) according to  claim 3 , wherein the flame retardant polypropylene composition (C) is free of halogens. 
     
     
         17 . The flame retardant polypropylene composition (C) according to  claim 3 , wherein the overall amounts of the propylene polymer (PP), the nitrogen-containing flame retardant (FR), the antidripping-agent (A) and optionally the carbon black (CB) together make up at least 90 wt.-% of the flame retardant polypropylene composition (C). 
     
     
         18 . The flame retardant polypropylene composition (C) according to  claim 3 , wherein the nitrogen-containing flame retardant (FR) comprises a first nitrogen-containing phosphate (FR1) and a second nitrogen-containing phosphate (FR2). 
     
     
         19 . The flame retardant polypropylene composition (C) according to  claim 18 , wherein the weight ratio between the first nitrogen-containing phosphate (FR1) and the second nitrogen-containing phosphate (FR2) is in the range of 60:40 to 40:60. 
     
     
         20 . The flame retardant polypropylene composition (C) according to  claim 18 , wherein the first nitrogen-containing phosphate (FR1) is melamine polyphosphate and the second nitrogen-containing phosphate (FR2) is piperazine pyrophosphate. 
     
     
         21 . The flame retardant polypropylene composition (C) according to  claim 3 , wherein the heterophasic propylene copolymer (HECO) has:
 i) a comonomer content in the range of 4.0 to 17.0 mol-%, and/or   ii) a xylene cold soluble fraction (XCS) in the range of 7.0 to 25.0 wt.-%, based on the overall weigh of the heterophasic propylene copolymer (HECO).   
     
     
         22 . The flame retardant polypropylene composition (C) according to  claim 21  wherein the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO) has:
 i) a comonomer content in the range of 25.0 to 65.0 mol-%, and/or 
 ii) an intrinsic viscosity (IV) measured according to ISO 1628/1 (at 135° C. in decalin) below 3.5 dl/g. 
 
     
     
         23 . The flame retardant polypropylene composition (C) according to  claim 3  wherein the high melt strength polypropylene (HMS-PP) has a melt flow rate MFR 2  (230° C., 2.16 kg) determined according to ISO 1133 in the range of 0.5 to 15.0 g/10 min.